Self-sealing closure tube



c. R. SWARTZ SELF-SEALING CLOSURE TUBE Filed May 25, 1951 arc TOR. qua ns 0. SWARTZ ATTORNEY i atented Mar. 2, 1954 UNITED STATES PATENT OFFICE SELF-SEALING CLOSURE TUBE Curtis E. Swartz, Suflield, Ohio Application May 25, 1951, Serial No. 228,199

This invention relates to a self-sealing closure tube for a tube package of paste-like material, such as, for example, toothpaste, soap, prepared mustard, etc. The opening in the closure tube is such that when pressure is applied to the tube package, the opening is enlarged by the pastelike material which is extruded through it; but when the pressure is discontinued the closure seals itself by substantially reducing the size of the opening. The opening may be closed entirely, although generally this is not necessary.

The closure is made of rubber. It is tubular with a relatively blunt end. The opening is in this blunt end. It is slit-like and is preferably a straight-line, diametric opening, but may be three pronged, etc. The portions of the blunt end which form the opening are thick and wedgelike, and function without substantial dependence on the elastic properties of the rubber of which they are formed.

The closure tube includes a passage from the tube package to the opening. This passage is formed in part of the wedge-like portions which form a wedge-shaped space which tapers towards the opening. The walls of the passage which connect these tapering or wedge-like portions are thin and elastic. When pressure is applied to the tube package the pressure of the paste-like material extruded against the inner, tapering surfaces of the wedge-like portions in the passage of the closure tube causes the opening to widen. The thin walls which connect the wedge-like portions both at the ends of the opening and in the passage stretch and the opening widens without any substantial distortion of the wedge-like portions. This is true whether the opening is linear, or is formed of slits emanating from a center. When the pressure on the tube is discontinued these thin walls contract to normal size and bring the wedge-like portions toward one another, shutting the opening entirely or nearly so.

The closure tube may be triangular, quadrilateral or any desired shape but is preferably cylindrical. Although the outside dimensions of the wall of the closure tube are preferably constant, the closure tube may become larger or smaller as the blunt end is approached.

Generally the inner and outer surfaces of the wall of the closure tube will be smooth and the opening defined by this wall will be sufficiently smaller than the outlet of the tube package to permit the closure tube to be held by merely stretching it over the outlet. That portion of the wall which covers the outlet will generally be thicker than the portion at the ends of the opening. The end of the closure tube which is joined 2 Claims. (0 1. 222-490) to the outlet of the tube package may be of any suitable design. It may be thick and formed with a thread complementary to the thread on the outlet. It may be flared and held to the outlet by a coupling. The closure tube may be united to the tube of paste-like material in any desired manner.

The invention will be further described in connection with the accompanying drawings, in which Fig. 1 illustrates a tube package of paste-like material with the dispensing closure tube attached and the paste-like material being extruded through a diametrical slit-like opening therein.

Fig. 2 is an enlarged cross-section of the closure tube taken through the slit, on the line 2-4 of Fig. 1;

Fig. 3 is a cross-section of the closure tube at right angles to that shown in Fig. 2. and on line 3-3 of Fig. 2;

Fig. 4 is an end view showing the closure tube on the outlet of the tube package;

Figs. 5 and 6 are identical to Figs. 3 and 4 but show the change in the shape of the closure tube which occurs when paste-like material is extruded through the opening; and

Fig. 7 is a cross-section of a modified form of closure tube.

In Fig. l the dispensing closure tube 5 is stretched over the outlet of the tube package 6. The tube package may contain toothpaste or the like and a ribbon 'I of the contents is shown as being extruded through the outlet.

Figs. 2 and 3 show diflerent cross-sections of the preferred form of closure tube. The closure tube is made of rubber and the thickened wall Ill is stretched over the metal outlet ll of the tube package 6. The inner surface of the thickened wall In conforms to the threads on the metal or stifi plastic outlet II.

The rubber wall 13 of the closure tube which rises from the thickened portion I 0 is thinner and readily flexed. This thin wall connects the wedge-like portions l5 which are thicker and therefore stiiier than the thin wall I 3. The portions l5 form the end of the closure tube and the walls of the slit opening 16. The slit It extends along a diameter of the blunt end of the closure and the ends of the slit stop short of the circumference of the end, leaving the thin wall portion is intact across each end of the slit. The wedgelike portions l5 form a wedge-shaped space which tapers toward the slit opening l6. Preferably the edges of the wedges l5 do not quite meet at the slit.

When pressure is applied to the tube package the paste-like contents are forced through the outlet ll into the passage through the closure tube. The surfaces 18 of the wedges thin the paste-like material out to a ribbon as it reaches the slit Hi. The wedges are relatively stiff and inflexible. The thin walls l3 flex to permit the wedges to separate at the opening it against the restraining force of the thin walls 13, to permit the paste-like material to be extruded through the opening. Figs. 5 and 6 show the slit forced open with the thin walls [3 at each end of the slit stretched to permit the extrusion of the pastelike material through the slit. Fig. 5 illustrates how the wedges l5 flex without substantial dis-- tortion.

When the pressure on the tube is released the thin stretched walls 53 at the ends of the slit contract to substantially their normal proportions. The wedges iii are stifi so that the edges of the opening remain substantially straight and parallel. This eilectively closes the slit and seals off the paste-like material in the passage or the closure tube. The closure tube then resumes the shape shown in Fig. 3. The extent to which the slit closes depends upon the stiffness of the pastelike material and the elasticity of the thin walls l3. By suitably compounding the rubber and regulating the thickness of the walls it a closure may be designed which will almost entirely seal off paste-like materials of different consistencies.

Fig. 7 shows a modified closure tube with different means for fastening it to the outlet of a tube package. The closure tube is formed with wedge-like portions 20 which form the slit opening 2! identical with that illustrated in Figs. 1-6. The wall 23 is thin and flexible, and when pastelike material is extruded through opening 21 the wall flexes at 24, at the top of the coupling 25. This coupling is made of stiff plastic, metal or the like. It fits over the flange 28 at the bottom of wall 23, and screws on to the outlet 29 of tube package 38, and holds the closure tube in place.

The closure tubes of this invention may be sold with a tube package, either attached to the package or unattached. They may be sold, separately, if preferred. They may be provided with any suitable means for attaching them to a tube package. The slit opening formed by the stifi wedge members, etc., may even be constructed as a part of the. tube package.

What I claim is:

1. A dispensing closure tube for a flexible tube package containing paste-like material, which closure tube is made in one piece of rubber and is tubular and closed at one end, with a slit at the closed end through which the paste-like material is adapted to be extruded, the respective ends of the slit extending close to an edge of the closed end whereby there is only a thin wall of rubber at each end of the slit, there being a relatively thick wall .ofrubbenalong each side of theslit, the space within the closure tube being wedge-shaped and narrowing to the slit with the respective edges of the slit stifiened because of the amount of rubber therealong; whereby the opposite edges of the slit are maintained substantially parallel and the mass of the paste-like material as it is forced toward the slit by pressure on the tube package is gradually reduced in cross section and the portions of the closed end on opposite sides of the slit arespaced apart as the paste-like material is extruded therefrom, and when the pressure is discontinued the elasticity of the thin walls at the ends of the slit brings the edges of the slit toward one another to close the slit, said edges being stifiened and therefore remaining substantially parallel.

2. The. dispensing, closure tube of claim 1 in which the wall at the open end of the closure tube is thicker than the wall at the ends of the slit and is therefore more difiicultly stretched than said thinner wall and is adapted to hold firmly to the outlet of the tubepackage when stretched over it, and in which closure tube a relatively thin wall of rubber connects said thicker wall at the open end of the tube with the portion of the tube which encloses said wedge-shaped space whereby the portions of the end of the closure tube may be easily separated to open the slit.

CURTIS R. SWARTZ;

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,622,526 Lewis Mar. 29, 1927 1,647,215 Elsas Nov. 1, 1927 1,862,662 Costello June 14, 1932 2,569,073 Robinson Sept. 25, 1951 

